Epoxy organo-tin compounds



United States Patent ice 3,347,833?

Patented Oct. 17, 1967 I 2 393479833 salt thereof, with anepihalohydrin, preferably epichloro- EPGXY QRGANOEN (ZOMPOUNDS hydrin.The carboxylic acid derivatives are conveniently George Smith, Richmond,cane, assignor to Shell on produced from corresponding p (B-y y toCompany, New York, N.Y., a corporation of Delaware di-tin compounds- In-p g application of No Drawing. Filed Dec. 8, 1964, Ser. No. 416,881 5Smith, Ser. No. 407,243, filed Oct. 28, 1964, the produc- 7 Claims. (Cl.26078.4) tion of such B-cyanoethyl and fi-carboxyethyl tin compounds isdescribed in detail and is claimed. Broadly speaking,per(fi-cyanoethyl)monoto di-tin compounds ABSTRACT OF THE DISCLOSURE areproduced by electrolysis of aqueous solutions ofPer(B-carboglycidoxyethyl)monoto di-tin, useful as 10 acrylonitrile inthe presence of a tin cathode and an inert a precursor of epoxy resins,and the insoluble, infusible anode under conditions of a controlledcathode potential. material obtained by heating the tin compound with anIn general, aqueous electrolyte solutions containing from epoxy curingagent. about 3% by weight to about 30% by weight of acrylonitrile aresatisfactorily employed and the electrolysis is conducted attemperatures from about 0 C. to about 40 This invention relates toorgano-tin compounds pos- C., with the higher acrylonitrileconcentrations and higher sessing a multiplicity of epoxide moieties,and to cured reaction temperatures favoring the production of tetrakisproducts prepared therefrom. (,8-cyanoethyl)tin and the lowerconcentrations and re- It is often advantageous to incorporaterelatively large action temperatures favoring the production ofhexakis(,8- proportions of metal-containing compounds into epoxidecyanoethyl)ditin. resins. In general, the presence of substantialquantities of The success of the electrolysis procedure is based to ametal compound increases the weight of the resin and considerable extenton utilization of an electrolyte soluoften contributes to a moremetallic appearance which is tion having a pH above 7, but below about9.5, and conhighly desirable in certain applications. Conventionalducting the electrolysis at a controlled cathode potential, methods ofintroducing metal compounds into epoxy e.g., from about '1.6 volt toabout 2.0 volts vs. the resins generally comprise the addition of metalsalts as Saturated Calomel Electrode. From the per(;8-cyanoethcatalyticcuring agents and/ or promoters. However, beyl)monoto di-tin compoundsare produced by processes cause of the somewhat heterogeneous characterof the of basic hydrolysis, e.g., hydrolysis of the fi-cyanoethyl metalcompound-containing resins prepared in this mantin compounds in thepresence of alkali metal base, metal ner, the physical strength of theresin product is generalsalts, e.g., alkali metal salts, of theper(fi-carboxyethyl) ly decreased when substantial quantities of metalcommonoto di-tin compounds. These salts are acidified to pound areadded. It Would be of advantage to provide produce the correspondingper(,B-carboxyethyl)monoto organo-metallic compounds possessing epoxidegroups, di-tin derivatives, or alternatively the B-carboxyethyl tin fromwhich resins are prepared containing chemically r compounds are producedfrom the cyanoethyl derivatives bound metal moieties and containing acomparably high by acid hydrolysis. percentage of metal. The,B-carboxyethyl tin compounds, or alternatively the It is the object ofthis invention to provide novel orsalts thereof, particularly the alkalimetal salts, are regano-tin compounds which possess epoxide moieties,and acted with an epihalohydrin to produce the novel fi-carbthe novelcured products produced therefrom. An additional object is to provideepoxide-containing organo-tin oglycidoxyethyl compounds of theinvention. Although 40 other epihalohydrins such as epibrornohydrin andepicompounds having a high functionality with regard to iodohydrin areoperable, best results are obtained when the epoxide linkages present,that is, a multiplicity of epichlorohydrin is employed as the reactantand the use epoxide linkages per molecule. A further object is to proofepichlorohydrin in the production of the novel comvide novel cured epoxyresin products containing tin r pounds of the invention is preferred.which is chemically bonded within the polymer chain. The preparation ofthe B-carboglycidoxyethyl tin com- It has now been found that theseobjects are accornpounds is eflected by methods that are chieflyconvenplished by the provision of tin compound containing from tional.In one modification, the fl-carboxyethyl tin re- 1 to 2 tin atomswherein each free valence of the tin actant is admixed with an excess,e.g., a ten-fold excess,

atom(s) is satisfied by bonding to an ethyl substituent, the beta carbonatom of which is further substituted with a of epichlorohydrin, and analkali metal base, particularly an alkali metal hydroxide such aspotassium hydroxide,

carboglycidoxy substituent, and resins prepared therefrom. is addedthereto. The reaction mixture is maintained at The monomeric epoxyorgano-tin compounds of the an elevated temperature and the water formedduring reinvention are tetrakis(B-carboglycidoxyethyl)tin and action isremoved by distillation. It is frequentlyadvanhexakis(fi-carboglycidoxyethyl)ditin, which compounds aregenerically represented as per(B-carboglycidoxyethyl) tageous to employa catalyst in this modification and best results are obtained when atetraalkyl ammonium halide,

'monoto di-tin wherein the terminology per has the for example,tetramethylammonium bromide, is utilized.

conventional meaning in that all available valences of the This type ofglycidyl ester production is exemplified by monoto di-tin compounds aresatisfied by bonding to a the process of June et al., US. 3,075,999,issued Jan. 29,

[3-carboglycidoxyethyl moiety. Such compounds are fur- 1963.

ther illustrated by the formula In an alternate but generally preferredpreparation of Ii O 11 wherein n is a whole number from 0 to 1inclusive. the B-carboglycidoxyethyl tin compounds of the inven- The,B-carboglycidoxyethyl tin compounds of the intion, a metal salt,preferably an alkali metal salt, of the vention are customarily preparedby reaction of the corredesired B-carboxyethyl tin reactant is prepared,as by neusponding B-carboxyethyl tin compounds, or alternatively atralization of the corresponding carboxylic acid with alkali metalhydroxide or by alkaline hydrolysis of the appropriate fl-cyanoethyl tincompound, and is heated with an excess of epihalohydrin, also preferablyin the presence of a quaternary ammonium salt as catalyst. Subsequent toreaction, the more volatile product mixture components may be removed asby fractional distillation, whereupon the glycidyl ester product isrecovered and purified by conventional methods. This process type isillustrated by the disclosure of U.S. 2,537,981, issued Jan. 16, 1951,to Edwards.

As previously stated, the epoxy organo-tin compounds of theinvention'are materials from which useful tin-containing epoxide resinsare prepared. The epoxides of the invention have the structuraladvantage of offering a closely knit, polyfunctional character thatimparts to the resins prepared therefrom qualities of strength andresistance to the detrimental effects of heat. Through the use of'avariety of epoxy curing agents, the epoxy compounds of the invention arepolymerized but alternatively they may be mixed with other epoxycompounds such as other glycidyl esters, glycidyl ethers, epoxy alcoholsand the like and then cured, thereby producing copolymeric resins. Theepoxy organo-tin compounds may additionally be homopolymerized.

Preferred epoxy curing agents are those having active hydrogen atoms, asillustrated by the amines including trimethylenediamine,diethylenetriamine, diethylamine and p-phenylenediamine; polyamidesincluding the Versamides which are reaction products of polyamines andpolymerized fatty acids; and polycarboxylic acids including oxalic acid,phthalic acid and tetrahydrophthalic acid. Other suitable curing agentsinclude tertiary amines such as triethylamine, trimethylamine andbenzyldimethylamine; polycarboxylic acid anhydrides such asdodecenylsuccinic anhydride, methylnadic anhydride, phthalic an hydrideand hexahydrophthalic anhydride; and metal salts as illustrated by thecopper, zinc, and potassium salts of fiuoboric, sulfuric and phosphoricacids. In addition, the polysulfide resins, Lewis acids such as aluminumchloride and stannic chloride, and metallic hydroxides, e.g., sodiumhyroxide and potassium hydroxide, are also satisfactory curing agents.

The amount of curing agent required for curing the epoxy organo-tincompounds will vary over a considerable range, depending upon the agentselected. With curing agents having active hydrogen atoms, suitableamounts will vary up to and including stoichiometric amounts, that is,one mole of active hydrogen atom for each mole of epoxy group to bereacted. The other curing agents are typically empolyed in amountsranging from about 1% to about 20% by weight.

The epoxy organo-tin compoundsare cured bymixing with the curing agent.Although the cure will take place at room temperature, the cure isaccelerated by the application of heat, such as by effecting the cure attemperatures from about 50 C. to about 200 C. The cured products thusobtained are typically hard, infusible materials when highlycross-linked, or are somewhat elastomeric in'character when completecross-linking has not taken place. The resins are further characterizedby lack of solubility in common organic solvents such as ketones,alcohols, hydrocrabons and the like. The resin products are useful inadhesives, laminates, castings and coatings.

To further illustrate the novel epoxy organo-tin compounds of theinvention, and the polymeric products prepared therefrom, the followingexamples are provided. It should be understood that the details thereofare not to be regarded as limitations as they may be varied as will beunderstood by one skilled in this art.

Example I To 10.02 g. (0.3 mole) of tetrakis(fl-cyanoethyDtin was addeda solution of 4.8 g. (0.12 mole) of sodium hydroxide in 25 ml. of 50% byweight aqueous methanol. The suspension was refluxed for 67 hours bywhich time the evolution of ammonia had ceased. The clear light yellowsolution was evaporated to dryness to yield 15.2 g. of the tetra sodiumsalt of tetrakis(fi-carboxyethylfiin, a hygroscopic light cream solidwhich did not melt below 300 C. The infrared spectrum of the productshowed no nitrile absorption at 2240 cmf The elemental analysis was asfollows:

Anal. Calc. Found 0, percent wt, 28v 0 2S. 5 H, percent wt. 3. 2 3. 5Sn, percent wt 23. 7 21. 9 Na, percent at 18. 6 18.5

By similar procedure employing potassium hydroxide, the tetra potassiumsalt of tetrakis([i-carboxyethyl)tin was prepared, also a light creamhygroscopic solid.

Example 11 Anal. Calc. Found 0, percent wt a. 3

34. 9 11, percent wt 4. 8

Example III To 13.4 g. (0.0238 mole) of the tetra potassium salt oftetrakis(B-carboxyethyl)tin suspended in 92.5 g. (1.0 mole) ofepichlorohydrin was added 0.5 g. (0.032 mole) of tetramethylammoniumbromide and the stirred suspension was placed in an oil bath maintainedat 135 C. The refluxing mixture was stirred for 1 hour at which time theexcess epichlorohydrin was flashed off to leave a light yellow mobileoil. The oil was dissolved in methylene chloride, and subsequent tofiltration, the solution was washed with water, 5% aqueous sodiumbicarbonate and again with water. The solution was then dried and thesolvent removed by evaporation to yield 12.7 g. of a light yellow oil.The presence of tetrakis(B-carboglycidoxyethyl)tin in the product wasindicated by the infrared spectrum which contained characteristic esterand epoxide bands along with a small hydroxyl band, and by the followinganalysis for tin and epoxide content.

Anal. Cale. Found Epoxide value, eq/IOO g 0. 6.7 459 Sn, percent wt 1S.6 7

the tetrakis(B-carboglycidoxyethyl)tin product contained 56.4% of thetheoretical epoxide value and 79.5% of the theoretical tin content.

Example IV By a procedure similar to that of Example III, part 1, 9.03g. (0.01 mole) of the hexa potassium salt of hexakis(fl-caboxyethyDditin was reacted with 66.7 g. (0.72 mole) ofepichlorohydrin in the presence of 1.56 g. (0.01 mole) oftetra-methylammo'ni-um bromide. The product mixture containinghexakis(fi-carboglycidoxyethyl)ditin was obtained as a light yellow gumhaving the following Similar results were obtained when thecorresponding sodium salt of hexakis(fi-carboxyethyl)dithin wasemployed. From the reaction of 7 g. (0.00865 mole) of this sodium salt,and 48 g. (0.348 mole) of epichlorohydrin in the presence of 0.5 g.(0.0033 mole) of tetramethylammonium bromide was obtained 8.3 g. of alight yellow gum containing hexakis(l3 carboglycidoxyethyl)ditin whichhad 52.2% of theoretical epoxide value and 67.0% of the theoretical tincontent.

Example V With 2.55 g. of the tetrakis(B-carboglycidoxyethyl)tinprepared in Example III, part 1 (which represented 0.004 mole based onglycidyl ester), was mixed 1.805 g. (0.0116 mole) of hexahydrophthalicanhydride and 0.02 g. of benzyldimethylamine as catalyst. The viscousmixture was placed in a mold and cured in an oven at 80 C. for 3 hoursand at 120 C. for 5.5 hours. The product was a hard, infusible yellowsolid which was insoluble in common organic solvents such as acetone,methyl ethyl ketone, benzene, toluene, methanol and chloroform.

When a curing process similar to that above was utilized except that thecure was efiected at 8595 C. during 6.5 hours, the product was a lightyellow, infusible elastomeric material which was also insoluble incommon organic solvents.

Example VI To 2.04 g. (0.002 mole based on glycidyl ester) of thehexakis(B-carboglycidoxyethyl)ditin product of Example IV, part 1, wasadded 1.22 g. (0.00784 mole) of hexahydrophthalic anhydride and 0.01 g.of benzyldimethylamine. The mixture was cured for 3 hours at C. and for4 hours at 120 C. The resulting product was a clear yellow, hard,infusible solid which was not soluble in common organic solvents.

When the above experiment was repeated employing a cure time of 8.5hours at 95 C., the product was a light yellow, infusible plasticmaterial which was insoluble in common organic solvents.

Example VII A sample of a tetrakis (,d-carboglycidoxyethyl)tin productmixture prepared according to the procedure of Example III, part 1, andcontaining 48% of the theoretical epoxide value and 69% of thetheoretical tin content was allowed to stand at room temperature in thepersence of light for about 3 months. The resulting homopolymerpolymeric tetrakis(fi-carboglycidoxyethyl)tin, was yellow in color andelastomeric in character and was insoluble in common organic solvents.

I claim as my invention:

1. Per(fi-carboglycidoxyethyl)monoto di-tin.

2. Tetrakis (fi-carboglycidoxyethyl)tin.

3. I-Iexakis (,B-carboglycidoxyethyl)ditin.

4. The insoluble, infusible material obtained by heatingper(,B-carboglycidoxyethyl)monoto di-tin with an epoxy curing agent.

5. The insoluble, infusible material obtained by heatingper-(fl-carboglycidoxyethyl)monoto di-tin with an epoxy curing agentcontaining active hydrogen atoms.

6. The insoluble, infusible material obtained by heatingper(B-carboglycidoxyethyl)monoto di-tin with a polycarboxylic acidanhydride.

7. The insoluble, infusible material obtained by heatingtetrakis(ii-carboglycidoxyethyl)tin with a polycarboxylic acidanhydride.

No references cited. JOSEPH L. SCHOFER, Primary Examiner. J. KIGHT III,Assistant Examiner.

1. PER(B-CARBOGLYCIDOXYETHYL)MONO- TO DI-TIN.